An integral part of an aircraft fuselage is the door assembly through which passengers and crew enter and exit the aircraft. The door assemblies of modern commercial aircraft include latch mechanisms that lock the door in place when it is closed and unlock the door when it is opened. The actual opening and closing of the door assemblies are controlled by handle assemblies that actuate the latch mechanisms. Most of the handle assemblies are provided with interior and exterior handles so that the door assemblies in which they are installed may be opened or closed from either inside or outside the aircraft. Many of these door assemblies also include emergency escape slides and actuators that, when triggered, rapidly open the associated doors. Often, the emergency escape slide is arranged to be deployed in conjunction with the opening of the door by the associated actuator. When the actuator is triggered, the actuator will rapidly open the door and the escape slide will automatically inflate so as to facilitate rapid evacuation of the aircraft.
An aircraft door handle assembly is typically designed to perform a number of different functions and to operate properly regardless of the harshness of the environmental conditions to which it may be exposed. Most handle assemblies are constructed so that either the interior or exterior handle can be used to actuate the latching mechanism regardless of which handle was last used to actuate the mechanism. This is because when an aircraft door is closed prior to takeoff, it is impossible to know if upon landing, persons inside or outside the aircraft will want or need to open the door first. A handle assembly employed with an aircraft door assembly that includes an emergency actuator must be capable of deactivating the actuators from outside the aircraft. This is important, because with the door in an emergency mode, when the actuator is armed, persons inside and outside the aircraft may reach the door essentially simultaneously. If the actuator is triggered while someone is outside the aircraft, the door may rapidly open and automatically deploy the escape slide, either of which could then strike that individual. Thus, persons outside the aircraft need to be able to disarm the actuator so that they can open the aircraft door without risk of injury.
The typical handle assembly includes an exterior, or outside handle that is normally stored flush with the outer skin of the aircraft so as to not degrade the aerodynamic efficiencies of the fuselage. Regardless of the large pressure differentials that may develop between the inside of the aircraft, which is pressurized, and the outside low ambient pressure at high altitudes, the handle assembly must keep the outside handle locked in place so that it does not "pop out" in flight. Inadvertent extension of the outside handle can disrupt the airflow around the aircraft and degrade aerodynamic performance. Moreover, extension of the outside handle could lead to its movement so as to cause self-actuation of the handle assembly and the associated latch mechanism. With an unpressurized cabin this could result in the door inadvertently opening while the aircraft is in flight. Moreover, a handle assembly must also be designed to operate even though its exterior components may be exposed to significant amounts of rain or snow.
Aircraft door handle assemblies have been provided that meet one or more of these design criteria. These assemblies are often provided with secondary latch mechanisms. For example, some aircraft door handle assemblies are provided with latches that lock the outside handle in position and/or disarm the emergency actuator. Manipulation of these handle latches can lengthen the time needed to actuate the handles with which they are used. Some aircraft door handle assemblies are constructed so that they are integrally connected to the doors in which they are employed. In the event the handle assembly requires extensive maintenance, the assembly cannot be simply replaced; the whole of the aircraft must be taken out of service. Moreover, it has typically been necessary to construct these assemblies out of a large number of interlocking components. As a result, these aircraft door handle assemblies have proved to be both costly and difficult to manufacture and maintain.